The invention relates to a device and to a process for the galvanic deposition of aluminum from aprotic, organo-aluminum electrolytes which are free of oxygen and water.
A device and a process of this kind are known through the German Pat. No. 25 37 285. This known device includes of a heatable treatment trough which can be closed so as to be air-tight and which can be fed with an inert gas. A rotatable galvanizing drum is arranged inside the treatment trough, and a first container is connected to the treatment trough and serves to store the electrolyte. A second container is also connected to the treatment trough and serves to store a flushing liquid.
In this known device, the galvanizing drum must be removed from the galvanizing trough for loading and unloading, which is not only extremely complicated and time consuming, but also necessitates appropriately sized introduction and removal openings for the galvanizing drum.
As is known, air must be excluded from the organo-aluminum electrolyte which is produced under oxygen-free and hydrogen-free conditions. Any electrolyte contact with air, as a result of its reaction with oxygen and atmospheric moisture, results in a considerable reduction in the conductivity of the electrolyte and thus in its life duration. For this reason, galvanization using electrolytes of this kind must also take place under the exclusion of air. In the known device, this desired air exclusion can only be achieved by repumping the electrolyte back into its feed container in an inert or shield gas atmosphere following galvanization. Before the electrolyte is reintroduced into the galvanizing tank following the reloading of the galvanizing drum, the galvanizing tank must be flooded with an inert liquid and then returned to an inert gas atmosphere. This reintroduction process not only necessitates a considerable structural outlay but is also time consuming.
The German Pat. No. 25 37 256 and the German Pat. No. 27 16 805 disclose devices for the galvanic deposition of aluminum in which the components are treated in a galvanizing tank which is externally sealed and can be supplied with shield gas. The loading and the removal of the components which are to be galvanized is effected via airlock chambers which can be flooded with shield gas and which contain an externally operable workpiece transfer device. These known devices likewise necessitate a considerable structural outlay, and, in particular, the airlock chambers must be matched to the size of the components to be treated. Moreover, these known devices do not readily facilitate the treatment of bulk goods. In addition, it is extremely difficult to keep the airlocks completely sealed so that the danger always exists that the electrolyte will gradually suffer damage due to the diffusing in of air.